As the atom-smasher at Europe's CERN research center is readied for its official startup near Geneva on Wednesday, researchers might wish that the general public was captivated by the quest for the Higgs boson, the search for supersymmetric particles and even the evidence for extra dimensions.

But if the feedback so far is any guide, the real headline-grabber is the claim that the world's most powerful particle-smasher could create microscopic black holes that some fear would gobble up the planet.

The black-hole scenario is even getting its day in court: Critics of the project have called for the suspension of work on the European collider until the scenario receives a more thorough safety review, filing separate legal challenges in U.S. federal court and the European Court of Human Rights.

The strange case of the planet-eating black hole serves as just one example showing how grand scientific projects can lead to a collision between science fiction and science fact. The hubbub also has led some to question why billions of dollars are being spent on a physics experiment so removed from everyday life.

Why do it?
Michio Kaku, a theoretical physicist at the City College of New York, acknowledged that people often ask about the practical applications of particle physics. Even if physicists figure out how a particle called the Higgs boson creates the property of mass in the universe, how will that improve life on Earth?

"Sometimes the public says, 'What's in it for Numero Uno? Am I going to get better television reception? Am I going to get better Internet reception?' Well, in some sense, yeah," he said. "All the wonders of quantum physics were learned basically from looking at atom-smasher technology."

Kaku noted that past discoveries from the world of particle physics ushered in many of the innovations we enjoy today, ranging from satellite communications and handheld media players to medical PET scanners (which put antimatter to practical use).

"But let me let you in on a secret: We physicists are not driven to do this because of better color television," he added. "That's a spin-off. We do this because we want to understand our role and our place in the universe."

About those black holes ...The black holes that may (or may not) be generated by the Large Hadron Collider would have theoretical rather than practical applications.

If the collider's detectors turn up evidence of black holes, that would suggest that gravity is stronger on a subatomic scale than it is on the distance scales scientists have been able to measure so far. That, in turn, would support the weird idea that we live in a 10- or 11-dimensional universe, with some of the dimensions rolled up so tightly that they can't be perceived.

Video: Big Bang collider could test theories—and nerves
Some theorists say the idea would explain why gravity is so much weaker than the universe's other fundamental forces — for example, why a simple magnet can match the entire Earth's gravitational force pulling on a paper clip. These theorists suggest that much of the gravitational field is "leaking out" into the extra dimensions.

"It will be extremely exciting if the LHC did produce black holes," CERN theoretical physicist John Ellis said. "OK, so some people are going to say, 'Black holes? Those big things eating up stars?' No. These are microscopic, tiny little black holes. And they’re extremely unstable. They would disappear almost as soon as they were produced."

Not everyone is convinced that the black holes would disappear. "It doesn't have to be that way," said Walter Wagner, a former radiation safety officer with a law degree who is one of the plaintiffs in the federal lawsuit. Despite a series of reassuring scientific studies, Wagner and others insist that the black holes might not fizzle out, and they fear that the mini-singularities produced by the Large Hadron Collider will fall to the center of the earth, grow larger and swallow more and more of Earth's matter.

Ellis, Kaku and a host of other physicists point out that cosmic rays in space are far more energetic than the collisions produced in the Large Hadron Collider, and do not produce the kinds of persistent black holes claimed by the critics. In the most recent report, CERN scientists rule out the globe-gobbling black holes and the other nightmares enumerated in the lawsuit, even under the most outlandish scenarios. Wagner remains unconvinced, however.

"I don't think the knowledge we are going to acquire by doing such an experiment outweighs the risk that we are taking, if we can't quantify that risk. ... We need to obtain other evidence," he said.

Strangelets, monopoles and moreBlack holes aren't Wagner's only worry: He also is concerned that when the collider creates a soup of free-flying quarks, some of those quarks might recombine in a hazardous way — creating a stable, negatively charged "strangelet" that could turn everything it touches into more strangelets.

The lawsuit also suggests that magnetic monopoles — basically, magnets with only a north or a south pole, but not both — could be created in the collider and wreak havoc.

Physicists point out that such phenomena have never been seen, either in previous collider experiments or in the wide cosmos beyond Earth.

"The experiments that we will do with the LHC have been done billions of times by cosmic rays hitting the earth," Ellis said. "They're being done continuously by cosmic rays hitting our astronomical bodies, like the moon, the sun, like Jupiter and so on and so forth. And the earth's still here, the sun's still here, the moon's still here. LHC collisions are not going to destroy the planet."

But how will all those collisions benefit the planet?

"We don't justify CERN or other big particle accelerators on the basis of spin-offs or technology transfer," Ellis said. "Of course, we do have programs for that. Personally, I believe that the most important knowledge transfer that we can make is by training young people who then maybe go off and do something else. I think that's probably more important than some particular technological widget that we may develop.

"I think the primary justification for this sort of science that we do is fundamental human curiosity," Ellis said. "It's true, of course, that every previous generation that's made some breakthrough in understanding nature has seen those discoveries translated into new technologies, new possibilities for the human race. That may well happen with the Higgs boson. Quite frankly, at the moment I don't see how you can use the Higgs boson for anything useful."

Kaku takes a different view: He said physicists will have to do a better job of explaining the potential payoffs if they expect taxpayers to keep covering the multibillion-dollar cost of exploring the scientific frontier. He pointed to the example of the Superconducting Super Collider — a project planned for Texas that would have been bigger than the Large Hadron Collider, but was canceled by Congress after $2 billion had been spent.

"After that cancellation, we physicists learned that we have to sing for our supper," Kaku said. "The Cold War is over. You can't simply say 'Russia!' to Congress, and they whip out their checkbook and say, 'How much?' We have to tell the people why this atom-smasher is going to benefit their lives."

Forecasting future benefitsIf past physics experiments are any guide, the potential payoffs would likely come in three areas, Kaku said:

Telecommunications: The challenge of dealing with all the data created by past experiments led to the creation of the World Wide Web at CERN in 1990. In a similar way, the Large Hadron Collider could usher in an era of global distributed computing and more efficient mass data storage. A better understanding of the subatomic world could lead to breakthroughs in quantum computing and super-secure communication.

Medicine: Particle accelerators are already playing a fast-rising role in
cancer
treatment
and
medical imaging
. New technologies developed for the Large Hadron Collider could well find their way into hospitals of the future. The ultrasensitive photon detector built for the LHCb experiment is a prime example, said the project's deputy spokesperson, Roger Forty. "I think there will be some cross-pollination with medical applications," he told msnbc.com.

Energy: Kaku suggested that the insights gained from the Large Hadron Collider could be applied to developing new energy sources in the decades ahead — such as controlled fusion power. Those microscopic black holes might even play a long-range role in the energy quest. "Some people think that maybe black holes in outer space may be a source of energy for future civilizations," he said.

Looking even farther ahead, Kaku noted that a deeper understanding of the universe has always led to technological leaps. Harnessing mechanical power led to the steam engine and the industrial revolution of the 19th century. The unification of electricity and magnetism led to computers, lasers and other 20th-century wonders. Unlocking the secrets of the atom led to the triumphs and terrors of the nuclear age.

"Human history has been shaped by the progressive unraveling of gravity, electricity and magnetism, and the nuclear force," Kaku said. "Now we are at the brink of the granddaddy of all such unifications ... the unification of all forces into a super force. We think the super force is superstring theory, a super force that drove the big bang, that created the heavens and the earth, that drives the sun, that makes all the wondrous technologies of the earth possible."

Will that great revelation come from the LHC? Even Kaku thinks that would be too much of a giant leap. "The Large Hadron Collider will not open up a gateway to another universe," he said. "It will not open up a hole in space. But it will try to nail down the equations which would allow perhaps an advanced civilization to do precisely that, to manipulate the fabric of space and time."

How will the machine do that? Ironically, it takes bigger and bigger machines to unlock the smallest subatomic mysteries — and the Large Hadron Collider is the biggest Big Bang Machine ever built. With its tangles of wiring, twists of plumbing and 17 miles of supercooled magnets, the machine may well rank as one of the engineering wonders of the 21st century.